Now to Southern California, where a shooting late last night left 12 victims and the gunman dead. The shooting took place at a bar in Thousand Oaks, Calif., northwest of Los Angeles. One of the victims was a first responder, Ron Helus. He was a sergeant with the sheriff's department. The suspect, who is now dead, is 28-year-old Ian David Long. He lived in the nearby suburb of Newbury Park.

Joining us now is NPR's Martin Kaste. Hey, Martin.

MARTIN KASTE, BYLINE: Afternoon.

CHANG: So can you just bring us up to speed here? What's the latest on the investigation?

KASTE: Well, we're learning more about the police response last night. The California Highway Patrol and Ventura County sheriff's department responded apparently very quickly after those first 911 calls came in from the country-Western bar. And they responded very quickly at great cost. As you said, Ron Helus was killed.

And the preliminary information we have about the timeline is that he and the Highway Patrol officer went to that club about six minutes after the first report to challenge the shooter. And this is the training that law enforcement has been following for the last 20 years, especially since Columbine - that they should not wait for backup; they should not bulk up their forces first. They just need to get in there, interrupt the shooting. Of course that means there's a greater likelihood of getting killed for law enforcement.

CHANG: Right.

KASTE: And that's unfortunately what happened to Helus, who was a 29-year veteran at this department.

CHANG: Can you talk about how the attack itself - how it unfolded?

KASTE: Well, the basic account we have so far is that the shooter came in armed with a semi-automatic handgun, a Glock with an extended clip to hold more ammunition. He shot staff near the door, and then he started shooting people around the dance hall. And it was full of young people because it was holding a line dancing event for college students. As to how he died, we're not quite sure yet what the sequence of events was, whether - you know, how soon after that challenge. We're not sure also whether the gunshot wound that killed him was self-inflicted. It may be that that was the case.

CHANG: And what do we know so far about the alleged shooter, Ian David Long?

KASTE: Well, he was 28 years old. He's from California. He served in the U.S. Marine Corps, served a tour there in Helmand Province. My colleague at the Pentagon, Tom Bowman, reported earlier today that an official there said the suspected shooter was not a stellar Marine - was the quote. He actually had two infractions for shoplifting at a PX. But he was honorably discharged.

CHANG: And in civilian life, were there any signs of criminal activity? Did he have a criminal record?

KASTE: Speeding infractions and then an incident this spring in April when the sheriff in Ventura County says apparently the deputies were called to his home because he was acting irrationally. Mental health workers were called in to evaluate him, but they ultimately decided that he was not an immediate threat to himself or others, and he was not taken into custody or put under observation. So we have no motive known yet for this shooting. As is the case in so many of these mass shooters, you know, this doesn't appear to be a person who's really accomplished much in his life. There's no sign of a big philosophy or motive behind this yet as far as we can tell besides the urge to be violent and having a gun to act on that.

CHANG: But, you know, California's one of those states with what's commonly called a red flag law which can be used to temporarily take a gun away from someone who's been deemed a threat to himself or others. Was that ever used with Long?

KASTE: Yeah, we don't know yet. It doesn't look like there's any sign yet that it was. California - it was one of the pioneers. They passed their law in 2014. There have been several more laws like this passed around the country, especially since Parkland - this idea that you can temporarily take someone's weapons away if they're deemed a threat to themselves or to other people.

But the problem often is that, you know, you do need to petition a court. That's the case here in California. Usually a close family member or a law enforcement officer has to do that. There's a whole process here. You're depriving someone of their gun. In this case, his gun was legally bought. So if no one takes that step, it's not going to happen.